Re: [PATCH v2 4/7] tracing: Add synthetic event error logging

[Steven Rostedt]

On Mon, 12 Oct 2020 17:42:40 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Mon, 12 Oct 2020 15:18:06 -0500
> Tom Zanussi <zanussi@xxxxxxxxxx> wrote:
> 
> > +static char last_cmd[MAX_FILTER_STR_VAL];
> > +
> > +static int errpos(const char *str)
> > +{
> > +	return err_pos(last_cmd, str);
> > +}
> > +
> > +static void last_cmd_set(char *str)
> > +{
> > +	if (!str)
> > +		return;
> > +
> > +	strncat(last_cmd, str, MAX_FILTER_STR_VAL - 1);  
> 
> If I understand strncat() correctly, it will add 'n' + 1 bytes from str
> to last_cmd. That is, I think you want:
> 
> 	strncat(last_cmd, str, MAX_FILTER_STR_VAL - (strlen(last_cmd) + 1));
> 

Looking at the patch more, it only has one caller to last_cmd_set(),
and one caller to synth_err_clear().

Why not just clear on set?

-- Steve



> 
> > +}
> > +
> > +static void synth_err(u8 err_type, u8 err_pos)
> > +{
> > +	tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
> > +			err_type, err_pos);
> > +}
> > +
> > +static void synth_err_clear(void)
> > +{
> > +	last_cmd[0] = '\0';
> > +}
> > +